1. Field of the Invention
The present invention relates to engine mountings. In particular, it relates to rocket engine mounting systems adapted to accommodate an engine positioned in the interior of an on-flying missile stage.
2. Description of the Prior Art
Upon burn-out, a missile rocket engine becomes dead weight. Commonly such an engine will be jettisoned from the on-flying portion of such a missile. Thus, the engine mounting arrangement must also provide a release capability.
Engine mounting systems are confronted with unique design problems when it is desired to position the engine interior to an on-flying missile stage. Such location has been necessitated by the development of concepts such as submarine-launched missiles. A new generation missile may be constrained in size for compatibility with an existing submarine missile tube. Design necessity may cause an engine, for instance, to be positioned within the payload and missile shroud.
An external or conventionally located engine is commonly surrounded by a segment of the surface skin of the missile and may be separated from the missile along with the surrounding skin as if it were a separate and independent missile stage. Such an engine faces separation problems common to all missile "stages". New problems are encountered when the non-degradation of the surrounding functional portions of a missile stage is necessary for the success of the missile. Devices which separate the engine from the on-flying stages by means of explosive cords, although thoroughly adequate in many conventional situations, are inadequate for internally-mounted motors due to the uncontrolled spreading of shrapnel associated with such a removal technique.
Additionally, the interior positioning of the rocket engine introduces substantial torsion problems. The typical rocket engine is elongated, having an axis that coincides with that of the missile in which it is mounted. Such an engine can weigh thousands of pounds, creating its own inertial force independent of the rest of the missile. When operated from a submarine, two types of lateral forces may be encountered, those due to depth charges and those due to relative movement of the submarine and the surrounding water medium upon underwater launch. These are new design problems due to the new capabilities of present-generation missiles.
The present invention provides both minimal torsional stress on the missile and effective and non-degrading motor release by providing a bracket located approximately at mid-length of the rocket motor engaging a motor-encircling joint having a groove and unsymmetrically weakened cross-section. Torsion is economically minimized by the shortened moment arm via mid-length attachment while the unsymmetrically weakened fracture joint does not introduce shrapnel into the missile body.